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authorLasse Collin <lasse.collin@tukaani.org>2022-11-24 23:23:55 +0200
committerLasse Collin <lasse.collin@tukaani.org>2022-11-24 23:23:55 +0200
commit3be88ae071371caa279b44e13f4836fb178fe4ae (patch)
treeb5afaacaa76de62249c17531143d51c8962cc659
parentliblzma: Add lzma_filters_update() support to the multi-threaded encoder. (diff)
downloadxz-3be88ae071371caa279b44e13f4836fb178fe4ae.tar.xz
liblzma: Allow nice_len 2 and 3 even if match finder requires 3 or 4.
That is, if the specified nice_len is smaller than the minimum of the match finder, silently use the match finder's minimum value instead of reporting an error. The old behavior is annoying to users and it complicates xz options handling too.
Diffstat (limited to '')
-rw-r--r--src/liblzma/lz/lz_encoder.c14
-rw-r--r--src/liblzma/lz/lz_encoder.h9
-rw-r--r--src/liblzma/lzma/lzma_encoder.c11
3 files changed, 26 insertions, 8 deletions
diff --git a/src/liblzma/lz/lz_encoder.c b/src/liblzma/lz/lz_encoder.c
index 2dad7e5f..702582ce 100644
--- a/src/liblzma/lz/lz_encoder.c
+++ b/src/liblzma/lz/lz_encoder.c
@@ -293,11 +293,15 @@ lz_encoder_prepare(lzma_mf *mf, const lzma_allocator *allocator,
return true;
}
- // Calculate the sizes of mf->hash and mf->son and check that
- // nice_len is big enough for the selected match finder.
- const uint32_t hash_bytes = lz_options->match_finder & 0x0F;
- if (hash_bytes > mf->nice_len)
- return true;
+ // Calculate the sizes of mf->hash and mf->son.
+ //
+ // NOTE: Since 5.3.5beta the LZMA encoder ensures that nice_len
+ // is big enough for the selected match finder. This makes it
+ // easier for applications as nice_len = 2 will always be accepted
+ // even though the effective value can be slightly bigger.
+ const uint32_t hash_bytes
+ = mf_get_hash_bytes(lz_options->match_finder);
+ assert(hash_bytes <= mf->nice_len);
const bool is_bt = (lz_options->match_finder & 0x10) != 0;
uint32_t hs;
diff --git a/src/liblzma/lz/lz_encoder.h b/src/liblzma/lz/lz_encoder.h
index e249beba..41439408 100644
--- a/src/liblzma/lz/lz_encoder.h
+++ b/src/liblzma/lz/lz_encoder.h
@@ -220,6 +220,15 @@ typedef struct {
// are called `read ahead'.
+/// Get how many bytes the match finder hashes in its initial step.
+/// This is also the minimum nice_len value with the match finder.
+static inline uint32_t
+mf_get_hash_bytes(lzma_match_finder match_finder)
+{
+ return (uint32_t)match_finder & 0x0F;
+}
+
+
/// Get pointer to the first byte not ran through the match finder
static inline const uint8_t *
mf_ptr(const lzma_mf *mf)
diff --git a/src/liblzma/lzma/lzma_encoder.c b/src/liblzma/lzma/lzma_encoder.c
index 788bcd1f..9a64b71f 100644
--- a/src/liblzma/lzma/lzma_encoder.c
+++ b/src/liblzma/lzma/lzma_encoder.c
@@ -492,7 +492,8 @@ set_lz_options(lzma_lz_options *lz_options, const lzma_options_lzma *options)
lz_options->dict_size = options->dict_size;
lz_options->after_size = LOOP_INPUT_MAX;
lz_options->match_len_max = MATCH_LEN_MAX;
- lz_options->nice_len = options->nice_len;
+ lz_options->nice_len = my_max(mf_get_hash_bytes(options->mf),
+ options->nice_len);
lz_options->match_finder = options->mf;
lz_options->depth = options->depth;
lz_options->preset_dict = options->preset_dict;
@@ -643,10 +644,14 @@ lzma_lzma_encoder_create(void **coder_ptr,
coder->dist_table_size = log_size * 2;
// Length encoders' price table size
+ const uint32_t nice_len = my_max(
+ mf_get_hash_bytes(options->mf),
+ options->nice_len);
+
coder->match_len_encoder.table_size
- = options->nice_len + 1 - MATCH_LEN_MIN;
+ = nice_len + 1 - MATCH_LEN_MIN;
coder->rep_len_encoder.table_size
- = options->nice_len + 1 - MATCH_LEN_MIN;
+ = nice_len + 1 - MATCH_LEN_MIN;
break;
}